Field of the Invention
The present invention relates to exposure apparatuses, exposure methods, and device manufacturing methods.
Description of the Related Art
Conventionally, alignment in a semiconductor exposure apparatus (a so-called “stepper” or the like) measures positions or positional error related to several shot regions set in advance on a substrate such as a semiconductor wafer, and a shot arrangement is then determined for the respective shot regions based thereon. What is known as “global alignment” is employed, where the respective shot regions are aligned in order on the wafer in positions corresponding to a master plate such as a reticle using the determined shot arrangement.
In addition to global alignment, magnification components and rotation components of the shot regions themselves are being corrected, with the aim of correcting distortion in the shapes of the shot regions caused by increased complexity in the manufacturing process, complexity that is a result of finer sizes, higher levels of integration, and higher angles of view being established in semiconductors. Such a technique is disclosed in Japanese Patent Laid-Open No. 2003-92252. A process of cutting a wafer thin, a process of laminating a thinned wafer to a support substrate under pressure, and so on are known as processes that produce distortion in the shapes of the shot regions. Meanwhile, Japanese Patent Laid-Open No. 2005-3965 proposes divided exposure, which divides a wafer into several exposure regions in accordance with positional deviation and exposes those regions rather than exposing the entirety of a single exposure region on the wafer, with the aim of further improving the precision of alignment.
However, wafers processed in a step-and-repeat semiconductor exposure apparatus have a large number of shot regions, and thus it is often the case that measuring alignment marks necessary for correcting distortion in the shapes of the shot regions takes time. There has thus been a problem in that correcting distortion in the shapes of the shot regions greatly reduces the throughput. There is an additional problem in that divided exposure makes it necessary to calculate the shapes of the regions obtained through the division, position deviation amounts, and so on, which reduces the throughput even further.